1. Field of the Invention
One aspect of the present invention relates to a mobile apparatus.
2. Description of the Related Art
A wireless communication apparatus selects a mobile communications network to start a connection when it is turned ON. At this time, a long time is taken for searching a mobile communications network which can be connected, and an amount of power consumption is also large. Therefore, the mobile communications network is selected by using a Most Recently Used (MRU) list for storing information about a mode which indicates which radio access technology is used, a frequency band and a used channel number for a mobile communications network to which a mobile apparatus 1 has recently connected (see “CDMA Development Group Document #143”. It is note that MRU list is called as MRU table in that document). Information about the connected mobile communications network is added to the MRU when a synchronization with a base station belonging to the mobile communications network and reception of information necessary for standby are completed or when the mobile apparatus is located within a coverage of a mobile communications network whose System Identification (SID) and Network identification (NID) are changed.
Moreover, there has also been proposed a technique for storing information about a mobile communications network to be connected at a time when a power is OFF in order to rapidly select a mobile communications network at a time when the power is ON (see JP-A-2004-297784).
According to (DMA Development Group Document #143, information to access and establish connection to mobile communications network is registered in the MRU at a time when a synchronization with a mobile communications network and a receipt of information are completed. When a selection of the mobile communications network is to be performed by using the information registered in the MRU in a power-ON state, however, the selection cannot be accurately carried out in some cases. For example, when a power supply of the mobile apparatus is turned OFF and the apparatus is moved in a power-OFF state, and then the power supply of the apparatus is turned ON again in a moving destination in which a service is given through a different mobile communications network from a stored mobile communications network, the information stored in the MRU is not valid. For this reason, the stored information is to be sequentially selected by way of trial from an upper so that a connection to the wiring communication network is delayed.
On the other hand, in the invention described in JP A-2004-297784, information about a current mobile communications network is stored including not only above information which CDMA development group document says but also base station identification information when a power supply is to be turned OFF. However, it may not be desirable that the mobile communications network is selected by using information about a mobile communications network which is finally waited when a plurality of mobile communications networks using a plurality of wireless communication methods are present with their coverages overlapped. For example, in an integrated mobile communications system configured by coverage area including a base station through a Wide Band Code Division Multiple Access (WCDMA) and a base station through Global System for Mobile Communications (GSM), it is expected that only a waiting processing (A waiting processing is a standby processing to do various services via mobile communications network after discovering a base station to establish connection, for example, to originate a call, to wait for receiving an incoming call) through the WCDMA is performed and only information about the base station through the WCDMA is stored in the MRU when a power supply is turned OFF. Then, the mobile apparatus moves to another coverage area in which only GSM is present, i.e. there is no WCDMA, while the mobile apparatus is turned off. In this case, the information registered in the MRU is not useful any more because the MRU stores only information related to access to WCDMA and the MRU provides no information to acquire GSM system after moving that coverage area. Consequently, a useless search for a cell selection is occurred to cause a delay in a connection to a GSM cell.